NOTES AND MEMORANDA. 413 



artificial results due to our methods of manipulation as are 

 these mycelioid coagula. Already in another branch of 

 histological inquiry observers have been on their guard 

 against the deceptive appearances of membranes and fibres 

 produced by the coagulation of albuminous fluids when 

 acted upon by the hardening reagents used in the laboratory. 

 One of the most careful and accomplished of the younger 

 German histologists, Dr. Flemming, of Kiel, makes the 

 following remarks in a memoir on the " Anatomy and Phy- 

 siology of Connective Tissue " {' Archiv fiir Mikrosk. 

 Anatomic/ 1876, vol. xii, p. 396) : — " I have worked for 

 some time with this combination (osmic acid and anilin) , and 

 have found, as is well known, no doubt, to others, that one 

 must not accept as veritable structure all that it brings into 

 view. Notoriously, osmic acid, like other hardening re- 

 agents, produces coagulation of the albuminous fluids of the 

 body, such as blood, serum, and lymph, and the coagula 

 become deeply tinted with the anilin dye. In fact this kind 

 of coagulum can be obtained without previous application of 

 osmic acid by the action of the simple solutions of the anilin 

 pigments, most abundantly, as one might expect, by the use 

 of alcoholic solutions, but also by the use of aqueous solu- 

 tions. I would never undertake to say that membranous- 

 looking things, such as this treatment has yielded me, with 

 loose connective tissue, are really membranous and not 

 coagula." Professor Flemming observes that one can most 

 satisfactorily convince oneself of the occurrence of these 

 albuminous coagula in blood- and lymph-vessels by the study 

 of animals which have not been killed by bleeding (a case 

 which applies very well to the excised portions of tissue 

 studied by Dr. Klein), and, perhaps, best of all by the study 

 of embryos ; the parietal cavities and the vessels of the 

 latter are almost always, after treatment with osmic acid, 

 filled with coagulated masses which take up the staining. 



A knowledge of the simulation by these coagula of 

 definite organic form so closely as to mislead experienced 

 mycologists is the not unimportant result of the researches 

 of Dr. Klein and Dr. Creighton. 



